1. Technical Field
The present invention relates to a room-temperature-curable organopolysiloxane composition. More specifically, the present invention relates to a room-temperature-curable organopolysiloxane composition that cures at room temperature into a rubber whose surface is easily coated with paint to yield a delamination-resistant paint film. Moreover, after curing, staining of the surface of the rubber or any substrate ajacent to the rubber does not occur with this room-temperature-curable organopolysiloxane composition.
2. Prior Art and Problems to Be Solved by the Invention
Organopolysiloxane compositions that cure at room temperature to form rubber are used in a wide range of applications, for example, as sealants, electrical insulating materials, adhesives, moldmaking materials, and so forth. One example already known in this regard is comprised of compositions prepared from silanol-endblocked organopolysiloxane plus crosslinker that contains silicon-bonded hydrolyzable groups in Japanese Patent Application Laid Open (Kokai or Unexamined) Number Sho 48-15962 (15,962/1973), equivalent to U.S. Pat. No. 3,719,635, issued Mar. 6, 1973 to Clark et al and Japanese Patent Application Laid Open Number Sho 49-2853 (2,853/1974) and assigned to Shinetsu Chemical Ind. Co.
However, compositions of this type exhibit a poor paint coatability, and the application of paint to the surface of the cured rubber is highly problematic. In addition, after curing, staining gradually occurs on the surface of the rubber and on substrates adjacent to the rubber. A room-temperature-curable organopolysiloxane composition containing amino-functional alcohol has already been proposed with the goal of improving the paint coatability in Japanese Patent Application Laid Open Number Sho 58-215453 (215,453/1983) equivalent to U.S. Pat. No. 4,447,576, issued May 8, 1984, to Fukayama et al. While this composition does exhibit good paint coatability to some degree, the adherence to the paint is unsatisfactory, which ultimately results in delamination or peeling of the paint film. In order to eliminate the other problem described above (staining of the surface of the cured rubber and substrates adjacent to the rubber), the present inventors have already proposed room-temperature-curable organopolysiloxane compositions that contain drying oil Japanese Patent Application Laid Open Number Sho 62-1750 (1,750/1987) assigned to Toray Silicone KK equivalent to European Patent Publication No. 210,442, and Japanese Patent Application Laid Open Number Sho 62-7763 (7,763/1987) equivalent to U.S. Pat. No. 4,683,251, issued Jul. 28, 1987, to Mikami. These compositions exhibit excellent anti-staining properties, but the drying oil can separate during storage and the surface of the cured rubber can become discolored.
Ona et al in U.S. Pat. No. 4,978,363, issued Dec. 18, 1990, describe a reaction product of an organopoly-siloxane having at least one amino-substituted hydrocarbon radical bonded to a silicon atom and a higher fatter carboxylic acid. The carboxylic acids can be either saturated or unsaturated. These reaction products are used as fiber-treatment that does not gel during use.